UKAEA Journals

Showing 1 - 6 of 6 Journals Results
2019
UKAEA-CCFE-PR(19)20

The paper presents an analysis of disruptions occurring during JET-ILW plasma operations covering the period from the start of ILW (ITER-like wall) operation up to completion of JET operation in 2016. The total number of disruptions was 1951 including 466 with deliberately induced disruptions. The average disruption rate of unintended disruptions i…

Preprint Published
2015
CCFE-PR(15)30

Asymmetrical disruptions may occur during ITER operation and they may be accompanied by large sideways forces and rotation of the asymmetry. This is of particular concern because resonance of the rotating asymmetry with the natural frequencies of the vacuum vessel (and other in-vessel components) could lead to large dynamic amplification of the for…

Preprint Published
2014

The edge equilibrium code (EEC) described in this paper is developed for simulations of the near edge plasma using the finite element method. It solves the Grad-Shafranov equation in toroidal coordinate and uses adaptive grids aligned with magnetic field lines. Hermite finite elements are chosen for the numerical scheme. A fast Newton scheme which …

Published
2014

A key feature of disruptions during Vertical Displacement Events (VDEs), discovered in JET in 1996, is the toroidal variation in the measured plasma current Ip, i.e. the plasma current asymmetries, lasting for almost the entire current quench. The unique magnetic diagnostics at JET (full set of poloidal coils and saddle loops recorded either from t…

Published
2012

This paper describes progress achieved since 2007 in understanding disruptions in tokamaks, when the effect of plasma current sharing with the wall was introduced into theory. As a result, the toroidal asymmetry of the plasma current measurements during vertical disruption event (VDE) on the Joint European Torus was explained. A new kind of plasma …

Published
2008

The theory of variances of equilibrium reconstruction is presented. It complements existing practices with information regarding what kind of plasma characteristics can be reconstructed, how accurately, and what remains beyond the abilities of diagnostic systems. The -curves, introduced by the present theory, give a quantitative assessment of quali…

Published